A variety of devices can be used to deliver drugs at desired treatment locations within a patient. For example, a drug-eluting stent (DES) can be positioned at the location of a stenosis (arterial narrowing) caused by arteriosclerosis. DESs generally include a drug containing polymer coated over a metal stent or scaffold, or a bioresorbable stent or scaffold composed of a drug-containing polymer. After a DES is delivered to a treatment location within a body lumen, it is expanded against a vessel wall and the drug is released via direct contact with the wall. Direct delivery of the drug to the vessel wall enables significantly lower doses than those required via other delivery means (e.g., pills or injections). However, depending on the design of the underlying stent or scaffold, 85% or more of the stented vessel wall area may not be in contact with the stent struts. Accordingly, significant diseased portions of the vessel wall may not receive a desired dose or delivery of the drug will not be uniform throughout the treatment site. Additionally, portions of the DES may be in contact with blood, arterial plaque and/or with other fluid or materials within the vessel lumen that are not intended delivery sites for the drug. These issues can result in drug tissue concentrations that are lower than desired or less uniform than desired.
Drug-eluting balloons (DEBs), and non drug-eluting balloons, provide an alternative to DESs, and can address some of the limitations discussed above. For example, DEBs can also be delivered to a desired treatment location and expanded against a vessel wall to release a drug. DEBs, however, can include a coating of the drug over an entire surface area of the balloon that expands to be in uniform contact with the vessel wall. Accordingly, DEBs can provide a more uniform dose to the adjacent vessel tissue. Additionally, when used in conjunction with angioplasty, the drug can be delivered at the location and time of any vessel damage that occurs during the procedure. Even so, DEBs also have several limitations. For example, during the delivery of the drug (i.e., when the balloon is inflated), blood flow in the associated vessel is stopped or severely obstructed, and no other treatment devices can be passed through the vessel. Additionally, both DEBs and existing DESs fail to provide drug-delivery at all locations along an adjacent vessel wall. Specifically, uneven vessel walls, obstructions, contours, or other features can prevent the balloon surface or stent struts from reaching portions of the vessel wall. Moreover, existing DESs and DEBs do not provide for drug-delivery into the vessel wall (i.e., penetration of the vessel wall for drug-delivery within the tissue itself).